Device for preventing film movement in still cameras

ABSTRACT

A camera for perforated roll film includes a transport mechanism for advancing film along an exposure plane and a metering mechanism for selectively disabling the transport mechanism. A film sensing pawl is movable by advancing film from an extended position traversing the film through a film perforation to a metering position spaced from the extended position in the direction of film advancement. A control member is movably mounted in the camera for movement with the sensing pawl and is associated with the metering mechanism for disabling the transport means when the sensing pawl reaches its metering position. A spring force on the control member urges the sensing pawl from its metering position toward its extended position. Means are provided for relieving the spring force on the sensing pawl at least during operation of the camers&#39;&#39;s exposure mechanism so that the spring force is not transmitted through the sensing pawl to the film.

United States Patent 1191 Beach f I [111 3,748,991 1451 July 31, 1973 1 DEVICE FOR PREVENTING FILM MOVEMENT 1 STILL CAMERAS David E. Beach, Penfield, NY.

[73] Assignee: Eastman Kodak Company,

. Rochester, N.Y.

22 .Filed: Aug. 21, 1972 [21] Appl. No.: 282,628

[75 Inventor:

[52] U.S. Cl. 95/31FM, 95/31 FL 511 11 1.01. .603!) 19/04 58 Field ofSearch ..95/3-1FM,31R,31FL;

[56] ,Rererems Cited a V'YUNITED STATES PATENTS I 3,603,236 9/1971 Engelsinann ..95/31FM 3,682,066 8/1972 Simon 95/31 FM 3,628,432 12/1911 Ettischer 95/31FM 3,148,605

9/1964 1 Peterson'et al. 242/714 X Primary Examiner-Richard L. Moses Attorney-W. H. Kline etal. I

[57] ABSTRACT A camera for perforated roll film includes a transport mechanism for advancing film along an exposure plane and a metering mechanism for selectively disabling the transport mechanism. 'A film sensing pawl is movable by advancing film from an extended position traversing the film through a film perforation to a metering position spaced from the extended position in the direction of film advancement. A control member is movably mounted in the camera for movement with the sensing pawl and is associated with the metering mechanism for disabling the transport means "when the sensing pawl reaches its metering position. A spring force: on the control member urges the sensing pawl from its metering position toward its extended position, Means are provided for relieving the spring force on the sensing pawl at least during operation of the camerss exposure mechanism so that the spring forceis not transmitted through the sensing pawl to the film.-

7 Claims, 6 Drawing Figures PATENTED JuLar ma SHEU 2 0F 3 DEVICE ron straints. a

v -srru. CAMERAS CROSS-REFERENCE TO RELATED I APPLICATIONS Reference is made to commonly assigned, copending U.S. Pat. applications Ser. No. 203,524, entitled FILM METERING; MECHANISM FOR CAMERAS, filed I BACKGROUND OF THE INVENTION" 1. Field of the Invention- I The present invention relates to cameras having. means for detecting the presence of a film perforation to selectively lock and release the film transport'mech-' anism, and more particularly to such cameras having 20' means for minimizing any surge of force from "the de-' tecting means onto the film during an exposure interval.

2. Description of the Prior Art The present invention is an improvement over cameras of the type disclosed in copending, coassigned U.S. Pat. application Ser. No. 203,524,'entitled"Film Metering Mechanism-for Cameras filed Dec. 1, 1971 in thename of David E. Beach. In the camera therein disclosed, a metering lever is movable. between an active position disabling the cameras film transport mechanism and an inactive position. A film sensing pawl is PREVENTING FILM MOVEMENT IN film is being advanced.'ln another preferred embodiment of the present'invention, the spring force on the mounted for movement from a retracted position engaging thefilm surface, through an extended position transversing the film when intercepting one of the film perforations, to a metering position spacedfrom the extended position in the direction of film advancement by the trailing edge of the perforation as the film is ad'- va nced.The' film sensing pawl and the metering lever are associatedsuch that the 'meterin'g.-lever is moved to its active position upon movement of the sensing pawl to its metering position. A spring urges the sensing pawl from its metering position towards its extended position and, since the metering pawl remains in the film perforation during exposure, the spring force is applied also to the trailing edge of the film perforation. This force on the film is opposed by frictional forces between camera elements and between the film and camera and/or cartridge surfacesawhen the shutter is tripped,-

minor vibrations travel through the camera; .These vibrations may relieve static friction wherever it occurs within the camera. Loss of frictional forcesrestraining the film can cause thespring force on the film fromlthe pawl to move the filmduring exposure.

. SUMMARY OF THEINVENTION} It is an object of the present invention to reduce or eliminate the possibility. of film movement during the exposure period by'eliminating or reducing the force of the-film-sensing pawl on the trailing edge of the film perforation during a picture-taking operation when the camera vibrations'can suddenly relieve frictional re- In a preferred embodiment of-the invention, this object has been accomplished by physically removing the spring which applies. the force to the spring sensing pawl from contact with the sensing pawl'except when sensing pawl is removed upon actuation of the cameras shutter release lever. In yet another preferred'embodiment, the spring force is reduced when film is not being advanced.

The invention, and its objects and advantages, will become-more apparent in the detailed'description of the preferred embodiments presented below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3is a view of a portion of a camera in accor .dance'with a second embodiment of the present invention showing the camera elements in their positions ready to make an exposure; FIG. 4 is a view similar to FIG. 3 ing shutter release;

FIG. 5 isaqview of a portionofa camera in accordance with yet'another embodiment of thepresent invention and showing the camera elements in their posiimmediately follow- .tions ready'to'make an exposure; and

FIG. 6 is a view similar to FIG. 5"showing the-camera elements as film is being advanced. v r r 1 DESCRIPTION OFTI-IE PREFERRED EMBODIMENTS Because cameras are well known, the presentdescription will be directed in particular to elements forming partof, or cooperating more directly with, apparatus in accordance with the present invention. It is to be understoodthat camera elements not specifically shown or described may take various forms well known to those skilled in the art. I v I I EMBODIMENT or FIGS. l AND 2' I loaded. The film may be contained in a cartridge of the type shown in coassigned US. Pat. No. 3,! 38,081 which issued on June 23, 1964 to Hubert Nerwin.

vA slide member 22 is reciprocally mounted on housing 10 by a pin-in-slot arrangement. The slide member has arack with a plurality of teeth'24 in meshing engagement'with the teethLof a gear sector 26 coaxially rotatable with a gear 28. Rotation of gear 28in the direction of arrow 38 in FIG. 2 winds film in the direction of arrow 30. Gear 28 has teeth in meshing engagement with a ratchet pawl 32 rotatablymounted ongear sector-26 and biased by a spring Mintdengagement with the teeth ofgear 28 so that upon mov ement of slide member 22 in the direction of arrow 36 in FIG. 2, the rotary movement of gear sector 26 is transmitted to rotate gear 28 in the direction of arrow-38, thereby advancing film along the cameras exposure plane'in the direction of arrow 30. As slide member 22 is returned to the right by a spring 40, gear 28 is prevented from rotating in a counterclockwise direction by a leaf spring I 42 which cooperates with the teeth on a ratchet wheel- 44 on a gear 46 in meshing engagement with gear 28.

A shutter release lever 48 is pivotally mounted on the cam'erahousing and may be raised against the force-of a spring 50. Movement of shutter release lever 48 downwardly by spring 50 is limited by an abutment 52 on a high energy lever 54. Shutterrelease over48 has an arcuate portion 56. High energy lever 54 is pivotally mountedon housing and is biasedby spring 40 for rotation in a counterclockwise direction. Lever 54 is held against such rotation by tab 52 which latcheso er shutter release lever 48 until the shutter release lever is raised. 'A bent tabportion 58 on high energy lever 54 is alignedLwitha projection 60 on slide member 22 to cock the high-energy lever when the slide member I is moved to .theleft. a

A metering lever 62 10 by astud64and' carries a metering pawl 66 urged toward an active position in engagement with the teeth of ratchet 44 by-a spring 68;to prevent rotation of gear 28.'A tab 70 on metering lever 56 is in alignment with highenergy'lever 54. I

A filmsensing pawl 74 is mounted for rotational andlongitudinal movement onia stud 76 and is urged by a spring 78 toward film 12. A control member 80 is also totatablyicarried by stud 76 and is urged in a counterclockwise direction by a spring 82 so that a tab-84 on the control memberengages sensing pawl 74 to rotate the sensing pawljin a counterclockwise direction. A lever 86 is rotatably'carried by a stud 88 and has a first leg in alignment with .the lower portion of gear sector is rotatably carried on housing Y 26 and a second leg in alignment with a tab 90 on com trol member 80.

I OPERATION n I I FIG. 1. shows-the elements of a camer'ain their respective positions after the film has been advanced and whenthecamera is ready tobe operated to take a-pictui'e. Metering pawl 66 of lever 62 is in its active position inengagem'ent with ratchet 44' so that slide member 22 cannot be moved to the left to transport more film. Film sensing pawl74 is extended through perforation 14 and has been rotated in a clockwise direction by the'advancing film to a metering position. High energy lever54 has been put into'a cocked position by projection: 60 of the slide member and is held there againstthe force of spring by tab 52engaging the shutter release lever.

Slide member 22 has been returned to the right by spring 40, rotating 'gear sector 26 in a clockwise direction as it retumed. As the gear sector rotated, its lower end engaged the first leg of lever 86 to rotate the lever in.a counterclockwise direction. As the lever rotated, itssecondleg engaged tab.90 of the control member to rotate thei control member 80. against the force of spring 82, thereby relieving the force of that spring from sensing pawl 74 so that no side load is placed on 'film 12 :from spring 82. Thus, when the shutter is tripped in a manner described in above-mentioned U.S.- Pat. application No. 203,524 and came ravibrations are set up, there is no load on film sensing pawl 74 which might cause film movement to the right due to the loss of frictional resistance as mentioned hereinbefore.

Afteran exposure has. been made, slide 22 may be moved to the left to advance the next film exposure area into alignment with .thej'cameras optical system.

As shown in FIG. 2, movement of the slide member to the left rotates gear sector 26 in a counterclockwise direction, thereby removingthe lower portion of the gear sector from the first leg of lever 86.'Sensing pawl 74 is cammed from the perforation in a manner described in application No. 203,524, and spring 82 is now free to rotate control member in a counterclockwise direction causing, through tab 84, similar rotation of sensing pawl 74 to a position shown in FIG. 2 in which the sensing pawl rests on the film surface awaiting'the arrival of the next succeeding film perforation. When the perforation reaches the'sensing pawl, spring 78 causes the. pawl to move to an extended position through the perforation so that continued movement of the film will pull the sensing pawl to its metered position shown in FIG. 1 to cause the cameras metering mechanism to disable the transport means as also explained in abovementioned US. Pat. application No. 203,524.

As soon as slide member 22' is released, spring 40 returns the slide member to its position shown in FIG. 1 and lever 86 once again rotates control member 80 in a clockwise direction to relieve the force of spring 82 from the film. I I i l EMBODIMENT OF FIGS. 3 AND 4 In FIGS. 3 and 4, I have shown a second embodiment of the present invention wherein the same reference numerals used torefer to elements inthe first embodiment have been usediwhen no change has beenmade to those elements. New reference numerals have been assigned to new or modified; elements.

Film sensing pawl 74 has been unchanged, and control member 80 is provided with a tab 92 (replacing tab of the first embodiment). High energy lever 54 has a latch member 94 pivoted againsta stop 96 ,by a spring 98.,Latch member 94 cooperates with a pin. 100 on a shutter release lever 102 which is spring urged upwardly by a spring 104 and may be moved downwardly in the direction of arrow 106 in FIG. 4 to remove pin 100 from latch member 94 so that spring 40 may drive high energy lever54 in a counterclockwise direction to trip the camerasshutter mechanism, and by engagement with tab 70 on metering lever'62, withdraw metering pawl 66 from ratchet 44. It can be seen that after an exposure, movement of projection 60 to the left during film advancement pushes high energy lever 54, by way of tab 58 sothat latch member 94 passes over pin 100 to cock the shutter and to hold the high energy lever until shutter release lever 102 is again depressed.

Referring to FIG. 4, when the shutter release lever is depressed, its lower end portion engages tab 92 on in-' termediate member 80 to rotate the intermediate member against the force of spring 82 in a clockwise direction to remove tab 84 from engagement with film sensing pawl 74. l J

Comparing the embodiments of FIGS. 1 and 2 and FIGS. 3 and 4,. it can be seen that the force of spring 82 is removed from film sensing pawl 74 except when film is being advanced in the first of said embodiments, and is removed from film sensing pawl 74 when the camera is actuated to take a picture in the second of the embodiments. In both instances, the side load on film 12 from the film sensing pawl is eliminated at least during the interval when the shutter is activated so that such force does not tend to move the film.

EMBODIMENT OF FIGS. 5 AND 6 In the last illustrated embodiment, spring 82 of the first two embodiments has been replaced by a tension spring 108 having one end connected to control member 80 and the other end to an arm .110 which is mounted for movement with slide member 22. When the slide member is returned to, the right by spring 40, the force of spring 108 on control member 80vis reduced to a point where the side load on film 12 by sensing pawl 74 is minimal and the risk of film movement because of that force is slight.

As slide member 22 is moved to the left to advance film, arm .110 moves therewith to tension spring 108 and to thereby rotate control member 80 and 'film sensing pawl 74 in a counterclockwise direction, returning the film sensing pawl to its position ready to detect the arrival of the next film perforation at the pawl.

Because the tension of spring 108 is reduced except during film advance, the risk of film movement during exposure is similarly reduced.

The invention hasbeen described in detail with particular reference to preferred embodiments, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 7

lclaim: a 1

1. In a camera adapted to receive roll film perforated at predetermined metering intervals and having (1) transport-means for advancing received film along the cameras exposure plane, (2) an exposure mechanism for effecting exposure of the film at said exposure plane, (3) a film sensing member movable by advancing film from a first position extending into a film perforation advanced into alignment with said sensing member to a second position spaced from said first position along said exposure'plane in the direction of film advancement, (4) spring means, (5) a control member movable by said spring means into abutment with said sensing member to urge said sensingmember toward its first position; the'improvement comprising means associated with said control member for relieving the force of said spring means on said sensing member at least means is not being operated. 4

3. The improvement as defined in claim 1 wherein said spring force relieving means comprises means associated with said transport means and said control member for moving said control member away from said sensing member when said transport means is not being operated. v

4. The improvement as defined in claim 1 wherein said spring force relieving means comprises means associated with said transport means and said spring means for at least partially relieving the force of said spring means on said control member when said transport means is not being operated.

5. The improvement as defined in claim 1 wherein: saidexposure mechanism includes a shutter release lever movable in apredetermined direction to effect an exposure;.and v said spring force relieving means includes means associated with said shutter release lever for relieving the force of said spring means on said sensing member upon movement of said shutter release lever in said predetermined direction. 7 6. The improvement as defined in claim 5 wherein said means associated with said shutter release lever includes means for moving said control member away from said sensing means upon movement of said shutter release lever in said predetermined direction.

7. In a camera adapted to receive roll film perforated at predetermined metering intervals and having (I) an exposure mechanism operable to make an exposure,

(2) a shutter release lever movable to operate said exfilm sensing member movable by advancing film from a first position extending into a film perforation advanced into alignment with said sensing member to a second position in the directionof film advancement; the improvement comprising:

spring means for applying a resilient force to said sensing member in a direction urging said sensing member from its second position toward its first position; and means associatedwith said spring means and said I shutter release lever for at least partially relieving said resilient forceupon movement of said shutter release lever to operate said exposure mechanism.

a: a: a: 4: 1:. a 

1. In a camera adapted to receive roll film perforated at predetermined metering intervals and having (1) transport means for advancing received film along the camera''s exposure plane, (2) an exposure mechanism for effecting exposure of the fiLm at said exposure plane, (3) a film sensing member movable by advancing film from a first position extending into a film perforation advanced into alignment with said sensing member to a second position spaced from said first position along said exposure plane in the direction of film advancement, (4) spring means, (5) a control member movable by said spring means into abutment with said sensing member to urge said sensing member toward its first position; the improvement comprising means associated with said control member for relieving the force of said spring means on said sensing member at least during operation of said exposure mechanism.
 2. The improvement as defined in claim 1 wherein said spring force relieving means comprises means associated with said transport means and said spring means for relieving said force when said transport means is not being operated.
 3. The improvement as defined in claim 1 wherein said spring force relieving means comprises means associated with said transport means and said control member for moving said control member away from said sensing member when said transport means is not being operated.
 4. The improvement as defined in claim 1 wherein said spring force relieving means comprises means associated with said transport means and said spring means for at least partially relieving the force of said spring means on said control member when said transport means is not being operated.
 5. The improvement as defined in claim 1 wherein: said exposure mechanism includes a shutter release lever movable in a predetermined direction to effect an exposure; and said spring force relieving means includes means associated with said shutter release lever for relieving the force of said spring means on said sensing member upon movement of said shutter release lever in said predetermined direction.
 6. The improvement as defined in claim 5 wherein said means associated with said shutter release lever includes means for moving said control member away from said sensing means upon movement of said shutter release lever in said predetermined direction.
 7. In a camera adapted to receive roll film perforated at predetermined metering intervals and having (1) an exposure mechanism operable to make an exposure, (2) a shutter release lever movable to operate said exposure mechanism, (3) transport means for advancing received film along the camera''s exposure plane, (4) a film sensing member movable by advancing film from a first position extending into a film perforation advanced into alignment with said sensing member to a second position in the direction of film advancement; the improvement comprising: spring means for applying a resilient force to said sensing member in a direction urging said sensing member from its second position toward its first position; and means associated with said spring means and said shutter release lever for at least partially relieving said resilient force upon movement of said shutter release lever to operate said exposure mechanism. 